This invention is directed to a solder pot which utilizes a replaceable heating member which includes a monolithic ceramic element having resistance wires integrally formed therein which transfer heat to a thermal conducting member.
Solder pots are utilized to hold an amount of solder at a particular temperature for an extended period of time. This is very useful in certain assembly or other similar operations where it is necessary to repeatedly tin the soldering iron or the like. One such known soldering pot uses a typical nichrome wire heating element of the type found ten to fifteen years ago in soldering irons, wood burners and the like.
It is difficult to obtain a constant temperature output from these older style nichrome heating elements. In view of this, the above known solder pot included a bi-metal strip located in association with the container for the solder which served as one arm of a set of contact points which were wired in series with the heating elements. This served as a thermostat to regulate the temperature of the heating element.
This type of control, however, is disadvantageous in that continuous arcing across the contact points ultimately leads to deterioration of the same, with ultimate failure of the thermostat. Unless the thermostat is replaceable, failure of the thermostat would lead to ultimate failure of the solder pot.
Further, use of these bi-metal strips as thermostats represents a very imprecise method of temperature control. When the contact points controlled by the bi-metal strip are opened, this shuts off current flow to the resistance heating element. However, the residual heat in the resistance heating element, even after the bi-metal strip has flexed and opened the contact points, is still transferred to the container for the solder, elevating the container and the solder therein to a temperature higher than that at which the bi-metal strip flexes and opens the contact points. This is, in essence, an overshoot of the desired temperature. In order to overcome this problem in the prior known devices, the contact points would have to be set to open at a temperature less than the desired temperature of the solder in the solder container. this required a certain amount of trial and error in order to achieve the preferred solder temperature.